Seen a few of my friends have this and was looking into it. I'm pretty sure 10 years ago this would just have been a multiplayer mode on a normal game though? Sounds like it's good to play, but at most £20. The recent Steam reviews have slated it for going back on the promise of not charging for in game items.
Remember when the MOD community was about sharing some fun rather than milking people? I'm all for the Devs making the step up into the professional development scene on the back of a good mod. Maybe I was just spoilt by everything that was done on the back of Half-Life...?